// ===================================================================
// Author: Matt Kruse <matt@mattkruse.com>
// WWW: http://www.mattkruse.com/
//
// NOTICE: You may use this code for any purpose, commercial or
// private, without any further permission from the author. You may
// remove this notice from your final code if you wish, however it is
// appreciated by the author if at least my web site address is kept.
//
// You may *NOT* re-distribute this code in any way except through its
// use. That means, you can include it in your product, or your web
// site, or any other form where the code is actually being used. You
// may not put the plain javascript up on your site for download or
// include it in your javascript libraries for download. 
// If you wish to share this code with others, please just point them
// to the URL instead.
// Please DO NOT link directly to my .js files from your site. Copy
// the files to your server and use them there. Thank you.
// ===================================================================

// HISTORY
// ------------------------------------------------------------------
// May 17, 2003: Fixed bug in parseDate() for dates <1970
// March 11, 2003: Added parseDate() function
// March 11, 2003: Added "NNN" formatting option. Doesn't match up
//                 perfectly with SimpleDateFormat formats, but 
//                 backwards-compatability was required.

// ------------------------------------------------------------------
// These functions use the same 'format' strings as the 
// java.text.SimpleDateFormat class, with minor exceptions.
// The format string consists of the following abbreviations:
// 
// Field        | Full Form          | Short Form
// -------------+--------------------+-----------------------
// Year         | yyyy (4 digits)    | yy (2 digits), y (2 or 4 digits)
// Month        | MMM (name or abbr.)| MM (2 digits), M (1 or 2 digits)
//              | NNN (abbr.)        |
// Day of Month | dd (2 digits)      | d (1 or 2 digits)
// Day of Week  | EE (name)          | E (abbr)
// Hour (1-12)  | hh (2 digits)      | h (1 or 2 digits)
// Hour (0-23)  | HH (2 digits)      | H (1 or 2 digits)
// Hour (0-11)  | KK (2 digits)      | K (1 or 2 digits)
// Hour (1-24)  | kk (2 digits)      | k (1 or 2 digits)
// Minute       | mm (2 digits)      | m (1 or 2 digits)
// Second       | ss (2 digits)      | s (1 or 2 digits)
// AM/PM        | a                  |
//
// NOTE THE DIFFERENCE BETWEEN MM and mm! Month=MM, not mm!
// Examples:
//  "MMM d, y" matches: January 01, 2000
//                      Dec 1, 1900
//                      Nov 20, 00
//  "M/d/yy"   matches: 01/20/00
//                      9/2/00
//  "MMM dd, yyyy hh:mm:ssa" matches: "January 01, 2000 12:30:45AM"
// ------------------------------------------------------------------

var MONTH_NAMES=new Array('January','February','March','April','May','June','July','August','September','October','November','December','Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
var DAY_NAMES=new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sun','Mon','Tue','Wed','Thu','Fri','Sat');
//定义一个统一的Utils类
DateUtils={
	LZ : function(x){
		return(x<0||x>9?"":"0")+x;
	},
	// ------------------------------------------------------------------
	// isDate ( date_string, format_string )
	// Returns true if date string matches format of format string and
	// is a valid date. Else returns false.
	// It is recommended that you trim whitespace around the value before
	// passing it to this function, as whitespace is NOT ignored!
	// ------------------------------------------------------------------	
	isDate:function (val,format) {
		var date=DateUtils.getDateFromFormat(val,format);
		if (date==0) { 
			return false; 
		}
		return true;
	},
	// -------------------------------------------------------------------
	// compareDates(date1,date1format,date2,date2format)
	//   Compare two date strings to see which is greater.
	//   Returns:
	//   1 if date1 is greater than date2
	//   0 if date2 is greater than date1 of if they are the same
	//  -1 if either of the dates is in an invalid format
	// -------------------------------------------------------------------
	compareDates : function (date1,dateformat1,date2,dateformat2) {
		var d1=DateUtils.getDateFromFormat(date1,dateformat1);
		var d2=DateUtils.getDateFromFormat(date2,dateformat2);
		if (d1==0 || d2==0) {
			return -1;
		}
		else if (d1 > d2) {
			return 1;
		}
		return 0;
	},
	// ------------------------------------------------------------------
	// formatDate (date_object, format)
	// Returns a date in the output format specified.
	// The format string uses the same abbreviations as in getDateFromFormat()
	// ------------------------------------------------------------------
	formatDate : function(date,format) {
		format=format+"";
		var result="";
		var i_format=0;
		var c="";
		var token="";
		var y=date.getYear()+"";
		var M=date.getMonth()+1;
		var d=date.getDate();
		var E=date.getDay();
		var H=date.getHours();
		var m=date.getMinutes();
		var s=date.getSeconds();
		var yyyy,yy,MMM,MM,dd,hh,h,mm,ss,ampm,HH,H,KK,K,kk,k;
		// Convert real date parts into formatted versions
		var value=new Object();
		if (y.length < 4) {y=""+(y-0+1900);}
		value["y"]=""+y;
		value["yyyy"]=y;
		value["yy"]=y.substring(2,4);
		value["M"]=M;
		value["MM"]=DateUtils.LZ(M);
		value["MMM"]=MONTH_NAMES[M-1];
		value["NNN"]=MONTH_NAMES[M+11];
		value["d"]=d;
		value["dd"]=DateUtils.LZ(d);
		value["E"]=DAY_NAMES[E+7];
		value["EE"]=DAY_NAMES[E];
		value["H"]=H;
		value["HH"]=DateUtils.LZ(H);
		if (H==0){value["h"]=12;}
		else if (H>12){value["h"]=H-12;}
		else {value["h"]=H;}
		value["hh"]=DateUtils.LZ(value["h"]);
		if (H>11){value["K"]=H-12;} else {value["K"]=H;}
		value["k"]=H+1;
		value["KK"]=DateUtils.LZ(value["K"]);
		value["kk"]=DateUtils.LZ(value["k"]);
		if (H > 11) { value["a"]="PM"; }
		else { value["a"]="AM"; }
		value["m"]=m;
		value["mm"]=DateUtils.LZ(m);
		value["s"]=s;
		value["ss"]=DateUtils.LZ(s);
		while (i_format < format.length) {
			c=format.charAt(i_format);
			token="";
			while ((format.charAt(i_format)==c) && (i_format < format.length)) {
				token += format.charAt(i_format++);
			}
			if (value[token] != null) { 
				result=result + value[token]; 
			}else { 
				result=result + token; 
			}
		}
		return result;
	},
	// ------------------------------------------------------------------
	// Utility functions for parsing in getDateFromFormat()
	// ------------------------------------------------------------------
	_isInteger : function (val) {
		var digits="1234567890";
		for (var i=0; i < val.length; i++) {
			if (digits.indexOf(val.charAt(i))==-1) { return false; }
		}
		return true;
	},
	_getInt:function (str,i,minlength,maxlength) {
		for (var x=maxlength; x>=minlength; x--) {
			var token=str.substring(i,i+x);
			if (token.length < minlength) { return null; }
			if (DateUtils._isInteger(token)) { return token; }
		}
		return null;
	},
	// ------------------------------------------------------------------
	// getDateFromFormat( date_string , format_string )
	//
	// This function takes a date string and a format string. It matches
	// If the date string matches the format string, it returns the 
	// getTime() of the date. If it does not match, it returns 0.
	// ------------------------------------------------------------------
	getDateFromFormat : function (val,format) {
		val=val+"";
		format=format+"";
		var i_val=0;
		var i_format=0;
		var c="";
		var token="";
		var token2="";
		var x,y;
		var now=new Date();
		var year=now.getYear();
		var month=now.getMonth()+1;
		var date=1;
		var hh=now.getHours();
		var mm=now.getMinutes();
		var ss=now.getSeconds();
		var ampm="";
		
		while (i_format < format.length) {
			// Get next token from format string
			c=format.charAt(i_format);
			token="";
			while ((format.charAt(i_format)==c) && (i_format < format.length)) {
				token += format.charAt(i_format++);
				}
			// Extract contents of value based on format token
			if (token=="yyyy" || token=="yy" || token=="y") {
				if (token=="yyyy") { x=4;y=4; }
				if (token=="yy")   { x=2;y=2; }
				if (token=="y")    { x=2;y=4; }
				year=DateUtils._getInt(val,i_val,x,y);
				if (year==null) { return 0; }
				i_val += year.length;
				if (year.length==2) {
					if (year > 70) { year=1900+(year-0); }
					else { year=2000+(year-0); }
					}
				}
			else if (token=="MMM"||token=="NNN"){
				month=0;
				for (var i=0; i<MONTH_NAMES.length; i++) {
					var month_name=MONTH_NAMES[i];
					if (val.substring(i_val,i_val+month_name.length).toLowerCase()==month_name.toLowerCase()) {
						if (token=="MMM"||(token=="NNN"&&i>11)) {
							month=i+1;
							if (month>12) { month -= 12; }
							i_val += month_name.length;
							break;
							}
						}
					}
				if ((month < 1)||(month>12)){return 0;}
				}
			else if (token=="EE"||token=="E"){
				for (var i=0; i<DAY_NAMES.length; i++) {
					var day_name=DAY_NAMES[i];
					if (val.substring(i_val,i_val+day_name.length).toLowerCase()==day_name.toLowerCase()) {
						i_val += day_name.length;
						break;
						}
					}
				}
			else if (token=="MM"||token=="M") {
				month=DateUtils._getInt(val,i_val,token.length,2);
				if(month==null||(month<1)||(month>12)){return 0;}
				i_val+=month.length;}
			else if (token=="dd"||token=="d") {
				date=DateUtils._getInt(val,i_val,token.length,2);
				if(date==null||(date<1)||(date>31)){return 0;}
				i_val+=date.length;}
			else if (token=="hh"||token=="h") {
				hh=DateUtils._getInt(val,i_val,token.length,2);
				if(hh==null||(hh<1)||(hh>12)){return 0;}
				i_val+=hh.length;}
			else if (token=="HH"||token=="H") {
				hh=DateUtils._getInt(val,i_val,token.length,2);
				if(hh==null||(hh<0)||(hh>23)){return 0;}
				i_val+=hh.length;}
			else if (token=="KK"||token=="K") {
				hh=DateUtils._getInt(val,i_val,token.length,2);
				if(hh==null||(hh<0)||(hh>11)){return 0;}
				i_val+=hh.length;}
			else if (token=="kk"||token=="k") {
				hh=DateUtils._getInt(val,i_val,token.length,2);
				if(hh==null||(hh<1)||(hh>24)){return 0;}
				i_val+=hh.length;hh--;}
			else if (token=="mm"||token=="m") {
				mm=DateUtils._getInt(val,i_val,token.length,2);
				if(mm==null||(mm<0)||(mm>59)){return 0;}
				i_val+=mm.length;}
			else if (token=="ss"||token=="s") {
				ss=DateUtils._getInt(val,i_val,token.length,2);
				if(ss==null||(ss<0)||(ss>59)){return 0;}
				i_val+=ss.length;}
			else if (token=="a") {
				if (val.substring(i_val,i_val+2).toLowerCase()=="am") {ampm="AM";}
				else if (val.substring(i_val,i_val+2).toLowerCase()=="pm") {ampm="PM";}
				else {return 0;}
				i_val+=2;}
			else {
				if (val.substring(i_val,i_val+token.length)!=token) {return 0;}
				else {i_val+=token.length;}
				}
			}
		// If there are any trailing characters left in the value, it doesn't match
		if (i_val != val.length) { return 0; }
		// Is date valid for month?
		if (month==2) {
			// Check for leap year
			if ( ( (year%4==0)&&(year%100 != 0) ) || (year%400==0) ) { // leap year
				if (date > 29){ return 0; }
				}
			else { if (date > 28) { return 0; } }
			}
		if ((month==4)||(month==6)||(month==9)||(month==11)) {
			if (date > 30) { return 0; }
			}
		// Correct hours value
		if (hh<12 && ampm=="PM") { hh=hh-0+12; }
		else if (hh>11 && ampm=="AM") { hh-=12; }
		var newdate=new Date(year,month-1,date,hh,mm,ss);
		return newdate.getTime();
	},
	// ------------------------------------------------------------------
	// parseDate( date_string [, prefer_euro_format] )
	//
	// This function takes a date string and tries to match it to a
	// number of possible date formats to get the value. It will try to
	// match against the following international formats, in this order:
	// y-M-d   MMM d, y   MMM d,y   y-MMM-d   d-MMM-y  MMM d
	// M/d/y   M-d-y      M.d.y     MMM-d     M/d      M-d
	// d/M/y   d-M-y      d.M.y     d-MMM     d/M      d-M
	// A second argument may be passed to instruct the method to search
	// for formats like d/M/y (european format) before M/d/y (American).
	// Returns a Date object or null if no patterns match.
	// ------------------------------------------------------------------
	parseDate : function (val) {
		var preferEuro=(arguments.length==2)?arguments[1]:false;
		generalFormats=new Array('y-M-d','MMM d, y','MMM d,y','y-MMM-d','d-MMM-y','MMM d');
		monthFirst=new Array('M/d/y','M-d-y','M.d.y','MMM-d','M/d','M-d');
		dateFirst =new Array('d/M/y','d-M-y','d.M.y','d-MMM','d/M','d-M');
		var checkList=new Array('generalFormats',preferEuro?'dateFirst':'monthFirst',preferEuro?'monthFirst':'dateFirst');
		var d=null;
		for (var i=0; i<checkList.length; i++) {
			var l=window[checkList[i]];
			for (var j=0; j<l.length; j++) {
				d=DateUtils.getDateFromFormat(val,l[j]);
				if (d!=0) { return new Date(d); }
			}
		}
		return null;
	}	
};
